JAVASCRIPT

width 100% react-native

First, define Dimensions.

import { Dimensions } from "react-native";

var width = Dimensions.get('window').width; //full width
var height = Dimensions.get('window').height; //full height

then, change line1 style like below:

line1: {
    backgroundColor: '#FDD7E4',
    width: width,
},

width 100% react native

import { Dimensions } from 'react-native';

width: ${(Dimensions.get('window').width)}px;

Get React Native View width and height

import React from 'react'
import { View } from 'react-native'

export default function index() {
  const onLayout=(event)=> {
    const {x, y, height, width} = event.nativeEvent.layout;
    
  }
  return (
    <View onLayout={onLayout}>
      <OtherComponent />
    </View>
  )
}

how to take 100% width in react native

header : {
	height : 100,
  	backgroundColor: "favorite color",
    alignSelf: "stretch",
}

React Native Setting Height And Width

import React from 'react';
import { View } from 'react-native';

const Dimensions = () => {
  return (
 <View>
      <View style={{
        width: 50, height: 50, backgroundColor: 'powderblue'
      }} />
      <View style={{
        width: 100, height: 100, backgroundColor: 'skyblue'
      }} />
      <View style={{
        width: 150, height: 150, backgroundColor: 'steelblue'
      }} />
    </View>
   );
  };
export default Dimensions; 
      

how to set width 100 react native

line1:{
alignSelf: 'stretch',
}